Heater circuit and switch



y 22, 1934- G. R. BARKSDALE 1,960,179

HEATER CIRCUIT AND SWITCH Filed Dec. 24. l93l 4 Sheets-Sheet 1 A f N 8INVENTOR T '1 GEORGE R. BARKSDALE 55 kzs' all tarvzeys May 22, 1934.

G. R. BARKSDALE 60,179

HEATER CIRCUIT AND SWITCH Filed Dec. 24 1951 4 Sheets-Sheet 2 ig.1.INVENTBEB GEORGE R. BARKSDALE @ZzaZ-Zvrneya y 1934- G. R. BARKSDALE,960,179

HEATER CIRCUIT AND SWITCH Filed Dec. 24, 1931 4 Sheets-Sheet 4 INVENTORGEORGE R. BARKSDALE Iraq-l5. {y 72:19 aZ-Z'arneys MMM Patented May 22,1934 UNITED STATES PATENT OFFICE HEATER CIRCUIT AND SWITCH ApplicationDecember 24, 1931, Serial'No. 583,122

.12 Claims.

This invention relates to the combination of electric switches andtranslating devices, or more particularly to heater units, with circuitconnections to current supply lines whereby thecurrent supplied to theheater units may be controlled. The invention is particularly useful inelectric stoves in which two or more heater units are employed.

The increase in use of electric stoves which derive their power from athree wire line is attended by the problem of properly balancing thecurrent drawn from the source of supply so that one side of the line maynot be unduly overloaded. Various ways have been devised in an attemptto solve this problem but none so far have been able to attain perfectbalance.

It is an object of my invention to provide a heater circuit includingmeans for controlling the heating units which will afford more perfectbalance than any known circuits.

Another object is to make a switch having its fixed and movable contactsarranged to make connections for high, medium, or low degrees of heat orno heat in a heater unit which the switch may control, and to vary theconnections between the outside wires of a three wire power line, andanother heater switch and its heater unit, to provide a more perfectbalance than was heretofore possible.

Other objects and advantages of my invention will be apparent as it isdescribed in connection with the accompanying drawings:

In the drawings- Figures 1 to 15 inclusive, show diagrammatical- 5 1y, apair of heater switches which control two heater units, the current forwhich is derived from a three wire supply line. The various figures showthe switches in all the positions they may occupy except the positionwith both switches off.

Figs. 16 and 17 are elevation section views through a special switchhaving contacts arranged according to the principles of my inven tion.The sections are taken on mutually perpendicular planes, as shown bylines 16--16 and 171'7 of Fig. 13.

Referring to the drawings, the three wire power line A, N, B, suppliestwo heating units QR, and ST, each having two elements Q and R and S andT, respectively. The delivery of current to the unit QR is controlledsolely by a switch 10. The delivery of current to the unit ST iscontrolled by the switch 50, but the arrangement of the connectionsbetween switch 50 and the power lines AB are subject to variation by theswitch 10 in order that a better balance of the system may be attainedas will hereinafter more clearly appear.

The switches 10 and 50 may be rotary snap switches which can be snappedaround in quarter turn steps and have a plurality of decks each deckhaving stationary and movable contacts. The movable switch members areall secured fixedly, in insulated relation, to a switch spindle 100 andare adapted to selectively engage the stationary switch members of theseveral decks as the spindle is rotated. The stationary switch membersmay be fixedly mounted in spaced circumferential positions, in anysuitable insulating switch base, around the switch spindle. An exampleof 'a suitable type of switch mechanism is shown in the Kempton PatentNo. 1,683,196 patented September 4th, 1928. The details of con structionof the switches 10 and 50 are not a part of this invention, since manyof the known rotary snap switch mechanisms could be used, if providedwith the proper number of decks and contact elements and (referring toswitch 10) arranged in the novel manner hereinafter set forth.

Assuming for the sake of illustration that the potential between lines Aand B is 220 volts and line N is the neutral, then the potential betweenthe lines N and either A or B will be 110 volts. The switches 10 and 50are connected, as will be hereinafter described in detail, to give threedegrees, of heat or no heat from each of the units QR and ST as theswitches are rotated through their successive quarter turns. Thesedegrees of heat are brought about by impressing the full 220 voltsacross elements Q, R, in series, or S, T, in series, in the high heatpositions, by connecting the units across the outside lines A, B; byim-- pressing 110 volts across one element, R or T for example, in themedium heat positions, by connections to the outside lines and theneutral; and by impressing 110 volts across Q, R, in series, or S, T, inseries, in the low heat positions, also by connections to the outsidelines and neutral. There are also off positions of each switch. Themeans and connections by which the above results are obtained will nowbe described.

The switch 10 comprises four decks 101, 102, 103 and 104. The first andsecond decks 101, 102 control the connections between the feed lines A,N, B, to the two element resistance unit QR so that high, medium, andlow heats may be obtained from the unit. The third and fourth decks 103,104 control the connections between the feed lines A, N, B, and theswitch 50 for the purpose heretofore indicated and hereinafter moreparticularly described. The switch 50 is a two deck switch having aswitch spindle 500 upon which are fixedly mounted, one above the other,two movable contact members having blades which are adamed to engagestationary contacts which are located in the planes of movement of themovable switch members. In function, in connection to the power linesand heater units, and in arrangement of its contact elements, switch 50is identical with the switch of the Kempton Patent 1,683,196, andtherefore is not further described except as is necessary to point outits relation with the other members of the circuit.

Referring particularly to switch the first deck 101 has two stationarycontacts 11 and 12, the latter being 90 in advance of the former, withlong blades projecting radially inward from the edge of the switch.These contacts are adapted to be engaged by all of the blades 15, 16 and17 of the movable switch member as it is rotated. The contact 11 isconnected directly to the neutral wire N of the three wire supply lineby wire 7 while contact 12 is connected to one end of the element R ofthe heating unit QR by wire 2. Diametrically opposite the long bladedcontact 11 is a sort bladed contact 13 which is connected directly tothe outside line A of the three wire supply line by wire 1.Diametrically opposite to the contact 12 is a short bladed contact 14which is connected directly to the intermediate point between theelements Q and R by intermediate connecting wire 6. The movable switchmember of the deck 101 comprises two short blades 15 and 17, extendingin opposite directions from the switch spindle, and a long blade 16 isarranged 90 in advance of the short blade 15. The short blades are notof sufiicient length to engage the stationary contacts 13 and 14.

ihe second deck of this switch has two long bladed stationary contacts21 and 23 in diametrically opposite positions around the switch spindleand a short bladed contact 22 arranged 90 in advance of contact 21. Themovable switch member of this deck 102 comprises a long contact blade24, which is adapted to engage all the stationary contacts as thespindle is rotated, and two short blades 25 and 26 which are arranged 90and 180 respectively in advance of the long blade 24. The long contact21 is connected directly to the outside end of the heating element Q bywire 3 while the short contact 22 is connected to the outside end of theheating element R by wire 2. The long contact 23 is connected to theoutside line B of the three wire supply system by wire 4.

Referring to switch the size and arrangement of the contacts of thisswitch and the connections to the heater unit ST are the same as thefirst two decks 101, 102 of switch 10 and their connections to unit QR.The connection of contact 511 to the neutral line N is also the same asthe connection between contact 11 and the neutral, but the power linesAB are not directly connected to the contacts 513 and 523 as in the caseof contacts 13 and 23. Since the connections between the stationarycontacts and the resistance elements and the power line N are identical,it would be undesirable to have the connections to the power lines A, B,identical also, because when the switches were in medium and lowpositions there would be a heavy unbalancing of the system since all thecurrent would be drawn from one side of the line and the neutral.

Therefore I have added the third and fourth decks to switch 10 and haveconnected the power lines A and B to these decks and have connectedwires and '70 between them and switch 50 in the manner about to bedescribed so that when the switch 10 is in medium and low position theelements of the heating unit QR which it con trols will be connectedbetween the neutral and the opposite power line from that to which theunit ST is connected when switch 50 is in medium and low" positions orwhen switch 10 is in high or off positions.

The third and fourth decks of the switch each have four stationarycontacts of equal size spaced 90 apart around the deck, and movableswitch members each comprising two arms one of which is 90 in advance ofthe other and each of which is of suflicient length to engage thestationary contacts in its own deck. In deck 103 the stationary contact31 is connected with the supply line B by wire 4, The contacts 32 and 34are connected together and to the wire 60 for delivering current to theshort contact 513 of the switch 50 from the outside feed lines A, B. Thecontact 33 is connected with supply line A by wire 1.

In deck 104, contacts 42 and 44 are connected together and with a wirefor delivering current to the long contact 523 of switch 50 from theoutside feed lines A, B. Contacts 41 and 43 are connected respectivelywith the supply lines B and A by wires 4 and 1.

The remaining connections to the switch 50 are as follows: Long contact512 in the deck 501 and short contact 522 in deck 502 are connected toone end of the heating element T by wire 2'. The intermediate pointbetween elements S and T is connected to short contact 514 in deck 501by wire 6' while the outside end of the heating element S is connectedwith long contact 521 of deck 502, by wire 3'.

By virtue of the structure and connections just described in certainpositions of the switch 10, the wires 60 and 70 are connected to thelines A and B respectively while in certain other positions of switch 10wires 60 and 70 are connected to lines B and A, respectively. By meansof this ability to shift the power line connections between wires 60 and70, I am able to obtain much more perfect balancing than has heretoforebeen possible, particularly when unit QR is of large capacity, say 2000Wand unit ST is of smaller capacity, say 1200W.

The circuit between the power lines and the heater QR, established bythe first two decks of switch 10, can be easily understood by referenceto the diagrams. In Figures 1, 5, 9 and 13, the switch 10 is in highheat position, the outer ends of the heater unit QR being connected tolines A and B as follows: Current flows from line A through wire 1 (seeFig. 5) to contact 13, through blades 16 and 15, through long contact 12and wire 2 to element R, through elements R, Q through wire 3 to longcontact 21, through blades 24, 26 long contact 23 and wire 4 to powerline B.

In Figs. 2, 6, 10, 14, the medium heat position of switch 10, thecircuit is as iol1ows: From line B through wire 4, long contact 23,blades 25, 24, short contact 22, wire 2, through element R throughintermediate connecting wire 6, short contact 14, long blade 16, shortblade 1'7, long contact 11, through wire 7 to the neutral N, of thepower lines.

In Figs. 3, '7, 11, 15, the low heat position of the switch 10, theconnections established are: from power line B, through wire 4 to longcontact 23, through blades 24, 26 and contact 21, 5

through wire 3 and heater unit QR, through wire 2, long contact 12,blades 17, 16, long contact 11, wire 7 to neutral wire N of the powerline.

Referring now to the connections established by switch 50, in Figs. 1,2, 3, 4, the switch is in high heat position. Current coming from oneoutside power line, goes through deck 103 of switch 100 to wire 60 thento short contact 513, long blade 516, short blade 515, long contact 512wire 2 to element T, through element S and wire 3', through long contact521, long blade 524, short blade 526, long contact 523, to wire '70,then through deck 104 to the outside power line.

Figs. 5, 6, '7, 8, show switch in position for establishing connectionsto give medium heat. Current from the power line is delivered to wire'70 through deck 104, then it goes through long contact 523, short blade525, long blade 524, short contact 522, connection 2, heater element T,in termediate connecting wire 6', short contact 514, long blade 516,short blade 517, long contact 511 and neutral-connecting wire 8.

Figs. 9, 10, 11 and 12 show switch 50 in position to give low heatconnections. Current coming through deck 104 goes through line 70 tolong contact 523, long blade 524, short blade 526, long contact 521,wire 3, unit ST, in series, wire 2, long contact 512, short blade 517,long blade 516, long contact 511, and neutral-connecting wire 8 to theneutral line N.

When switch 10 is in either high or off position, and switch 50 is ineither high or off position at the same time, there is no problem ofbalancing the load because there is no connection with the neutral inany of these positions. Therefore it is only necessary to have themedium and low connections arranged sothat the current drain will not beall on one side of the line when the switches are in medium or lowpositions. As hereinbefore indicated decks 103, 104 are provided toavoid this difliculty. Appropriate connections are made thereto so thatwhen the switch 10 is in high and off positions (perfect balanceposition for unit QR) lines and will be electrically connected to A andB respectively as shown in Figs. 1, 4, 5, 8, 9, 12 and 13.

In Figs. 1, 5, 9 and 13, i. e. when switch 10 is in high position,contact 33 (which is permanently connected to power line A throughwire 1) is connected to contact 34 (to which line 60 is connected) byblades 36, 35; and contact 41 (which is permanently connected to powerline B by wire 4) is connected to contact 42 (to which line '70 isconnected) by blades 45, 46. No current passes through line 60 in Figs.5, 9 and 13, however because in Fig. 13 the switch 50 is in offposition, while in Figs. 5 and 9, the current for medium and low heat inunit ST is obtained by connecting the unit to the neutral and power lineB as described.

In Figs. 4, 8 and 12, i. e. when switch 10 is off the contact 33 (whichis permanently connected to power line A through wire 1) is connected tocontact 32 (which is connected with line 60) by blades 35, 36, andcontact 41 (which is permanently connected to power line B through line4) is connected with contact 44 (to which line 70 is connected) byblades 46, 45. Again no current passes through line 60 in Figs. 8 and12, because the current for the medium and low heat in unit ST isobtained by connecting the unit to the neutral N and power line B, asdescribed.

In Figs. 2, 3, 6, '7, 10, 11, 14 and 15, the switch 10 is in medium andlow heat positions and lines 60 and 70 are connected to power lines Band A respectively.

In Figs. 2, 6, 10 and 14, i. e. when switch 10 is in medium positioncontact 31 (which is connected to power line B through wire 4) isconnected to contact 34 (to which line 60' is connected) by blades 35,36; and contact 43 (which is permanently connected to power line Athrough wire 1) is connected with contact 42 (to which line '70 isconnected) by blades 46, 45. Again in Figs. 6, 10 and 14, no currentflows through line 60 because in Fig. 14, switch 50 is in the offposition while in Figs. 6 and 10 current for the medium" and low" heatin unit ST is obtained by connecting the unit to the neutral N and powerline A, as described.

In Figs. 3, '7, 11 and 15, i. e. when switch 10 is in low positioncontact 31 (which is permanently connected to power line B by wire 4) isconnected to contact 32(to which wire 60 is connected) by blades 36, 35;and contact 43 (which is connected to power line A by wire 1) isconnected to contact 44 (to which line 70 is connected) by blades 45,46. Again, however, in Figs. 7, 11 and 15' no current flows through line60 because in Fig. 5 the switch 50 is in off position and in Figs. '7and 11, the current for medium and low heat in unit ST is obtained byconnecting the unit to power line A and neutral N, as described.

From the foregoing, it will be apparent that in the medium and lowpositions of switch 50 shown in Figs. 6, '7, 10 and 11, i. e. whenswitch 10 is in medium or low position the unit ST is connected withneutral N and power line A while on the other hand in the medium and lowpositions of switch 50 shown in Figs.

5, 8, 9, 12, i. e. when switch 10 is in high or off position, the unitST is connected with neutral, N and power line B. The unit ST istherefore shifted from its position across N-A to a position across NB.This shift is particularly advantageous when a third switch constructedexactly like switch .50 is connected to the power lines A, N, B, in justthe opposite way from the first two decks of switch 10. That is, withthe stationary contact equivalent to 513 connected directly tothe powerline B (instead of A as in switch 10) and with stationary contactequivalent to 11 connected directly to power line A. Even when thisthird switch is used, as in practical use of this invention it oftenwill be, the three switches will never be in a position where all theunits or elements thereof through which current is passing will be conne:ted between the same power line and neutral, at the same time. .Whenthe third switch controls a low capacity unit, say 1000W, then when allthe switches are in medium or low positions, the balancing will be verynearly the ultimate or perfect balance. Also when switch 10 is off andswitch 50 and the third switch are at medium, then the system willclosely approach a perfect balance, whereas in prior combinations markedunbalancing occurred when two such units were in medium position atonce.

Thus it will be apparent that I have made a circuit and switchcombination for control of electric heating units which has markedadvantages over similar circuit combinations of the prior art.

I do not limit my invention to the specific connections illustrated,since many changes within the scope of my invention will occur to thoseskilled in the art.

I claim:-

1. An electric circuit comprising a plurality of translating devices,and a plurality of circuit controlling means, in combination with athree line power supply, said circuit controlling means being adapted toestablish different connections between said devices and said supplylines to give different effects from said devices, and means controlledby one of said circuit controlling means for reversing the connectionsbetween another of said circuit controlling means and said supply lines.

2. An electric circuit comprising a plurality of heating units, and aplurality of circuit controlling means, in combination with a three wiresupply line, said circuit controlling means being adapted to establishdifferent connections between said heating units and said supply linesto give different degrees of heating, and means controlled by one ofsaid circuit controlling means for reversing the connections betweenanother of said circuit controlling means and said supply lines.

3. An electric circuit comprising a plurality of heating units, and aplurality of circuit controlling means, in combination with a three wiresupply line, said circuit controlling means being adapted to establishdifferent connections between said heating units and said supply linesto give different degrees of heating, and means controlled by one ofsaid circuit controlling means for reversing the connections betweenanother of said circuit controlling means and said supply lines, onlywhen said one circuit controlling means is in certain positions.

4. An electric circuit comprising a plurality of translating devices,and a plurality of circuit controlling means, in combination with athree wire power line, each of said circuit controlling means beingadapted to establish connections between said devices and said supplylines to give three different effects from said devices, and means toautomatically reverse the connections between said supply lines and oneof said circuit controlling means during the times when another of saidcircuit controlling means is in position to give two of said effects.

5. An electric circuit comprising a plurality of translating devices, aseparate circuit controlling means for each of said devices, incombination with a three line power supply, said circuit controllingmeans being adapted to establish connections between said devices andsaid supply lines to give a maximum effect or two intermediate effectsor no effect in each of said devices, and means controlled by one ofsaid circuit controlling means to automatically change the connectionsbetween said other circuit controlling means and the power lines so thatwhen the circuit controlling means are in positions to give theintermediate effects the translating devices will not be connected tothe same two of the power lines.

6. An electric circuit comprising a plurality of heating units, switchesfor each of said units, in combination with a three wire power supplyline, said switches being adapted to connect said heating units with thepower lines to give high, medium or low degrees of heat, and meansactuated by one of said switches, upon movement into "medium and lowpositions to establish connections between the power line and said otherswitch opposite to the connections established when said first switch isin high or off positions.

7. An electric circuit comprising a plurality of heating units, switchesfor each of said units, in combination with a three wire power supplyInc, said switches being adapted to connect said heating units with thepower lines to give high, medium or low degrees of heat, and meansacting automatically upon movement of one of said switches into mediumor low" positions to make connections so that the unit controlled by theother switch is not connected, when said other switch is in medium orlow positions, between the same two of the power lines as the unitcontrolled by said first switch.

8. An electric circuit comprising two heating units, switches forcontrolling said units in combination with a three wire supply line,said switches being adapted to make connections to impress fullpotential on each unit or half potential on part or the whole of eitheror both units and to cut off the units from the source, and means,actuated upon movement of one of said switches into position to impressless than full potential on the whole unit controlled thereby, toestablish connections between the other switch and the power lineswhereby, when said other switch is in position to impress less than fullpotential on the unit it controls, that unit will be connected on theopposite side of the power line from the unit controlled by said oneswitch.

9, An electric circuit comprising two heating units, a pair of switcheshaving a plurality of decks, each deck having movable and fixedcontacts, in combination with athree wire supply line, one of saidswitches controlling connections to one of said units to give high,medium and low degrees and to disconnect that unit, certain decks of theother of said switches controlling connec tions to the other of saidunits to give high, medium and low degrees of heat, and to disconnectsaid unit, certain other decks of said other switch changing theconnections between the power lines and said first switch when saidother switch is moved into certain positions.

10. An electric circuit comprising two heating units, a pair of switcheshaving a plurality of decks, each deck having movable and fixedcontacts, in combination with a three wire supply line, one of saidswitches controlling connections to one of said units to give high,medium and low degrees of heat and to disconnect that unit, certaindecks of the other of said switches controlling connections to the otherof said units to give high medium and low degrees of heat and todisconnect said other unit, certain other decks of said other switchshifting the connections between the power lines and said first switchwhen said other switch is moved into medium or low" position so thatsaid units are connected between the neutral and different outside powerlines when said first switch is moved into medium" or "low position.

11. An electric circuit comprising a plurality of translating devices, aplurality of circuit controlling means controlling the effect producedby said devices, in combination with a three wire power line, and meansfor reversing the relation of two of said power lines to one of saidcircuit controlling devices, said reversing means being operable byanother of said circuit controlling devices.

12. An electric circuit comprising a three wire power line, a pluralityof translating devices, a plurality of circuit controlling devices forgiving three different current effects in each of said rent effect inthe unit controlled by it, said circuit establishing means serving alsoto reverse said established relation when said other circuit controllingmeans is in its other two positions.

GEORGE R. BARKSDALE.

